Does anyone know some way to rotate a lot, ie change which side is the "front" one? I mean in some more automated way, and not open it in the Lot Editor and rotate and re-position the building and every single texture and prop. Changing the "Required Roads" property doesn't do the job.

afaik currently there isn't any method other than manually re-positioning.

Theoretically though, the position and rotational info of lot objects is stored in the reps. I'd imagine the wholesale rotation of lots could be automated by clever manipulation & translation of said reps.